Stabilizing means for movable roofs



Aug. 19, 1947. w.-. G. LAIRD 2,426,031

STABILIZING MEANS FOR A MOVABLE ROOF Filed May 3, 1944 NVENTOR WILBU R G.- LAIRD ATTORNEY.

Patented Aug. 19, 1947 @NETED STATES PATENT OFFICE STABILIZENG MEAN S FOR MOVABLE ROOFS Wilbur G. Laird, Pleasantville, N. Y.

Application May 3, 1944, Serial No. 533,869

16 Claims. i

This invention relates to improvements in fluid storage apparatus, and more particularly to storage containers or tanks provided with a vertically movable bell, lift or roof guided by a series of novel cable or chain snubbing units.

Large oil tanks are commonl provided with flexible or movable roofs, especially where volatile products are stored. An important development in this field of storage containers is the use of large upright cylindrical tanks with vertically movable lifts or bells which seal in a liquid in a launder at the top of the tank. Many types of stabilizers or guides have been proposed for such tanks. The guide or stabilizing means of the present invention is particularly suited for such lifts or bells but may be used to stabilize a roof or lift in either liquid or gas storage apparatus, or in apparatus used for the storage of both gas and liquid. According to the invention the lift, bell or roof may seal in a sealing liquid separate from the stored liquid or in the stored liquid, or be sealed with respect to the storage container by other means.

The primary object of the present invention is to provide a roof stabilizing means which is inexpensive but effective for keeping the roof level during its up and down movements.

Another object of the invention is to provide a roof stabilizing means which is accessible from the outside of the tank and roof and which is not subjected to the action of the stored gases, vapo s or liquids.

A further object of the invention is to provide an improved roof stabilizing means which is simple in operation and easy to install, inspect and repair.

A still further object of the invention is to provide a new and improved mechanism for keeping the vertically movable roof of a container for fluids in its normal position of movement with respect to the walls of the container, while at the same time allowing the roof to move up or down in response to the increase or decrease of the volume of fiuid in the container.

According to the invention, the apparatus for storing or holding fluids comprises an upright container, a roof or cover for the fluid to be held therein adapted to be supported by the fluid and to be moved up or down in response to increase or decrease of the volume of the fluid in the container. and means for restraining substantial tilting of the cove during such movement, said means preferably including several (more than two) spaced flexible inclined cable or chain snubbers of equal length distributed around said container and cover, each cable having one end anchored or attached to the covered a; substantial distance from its center such as on its rim and the other end anchored or attached to a fixed part of the apparatus such as the wall of the container, o launder, if a launder is used, or to the foundation if the tank is shallow, the cables being sufficiently long to allow for the desired rise and fall of the cover, each of the cables being attached to the cover and container at the same angle to the horizontal, and means for keeping the cables substantially taut at alltimes as by applying a rotational strain on the cover to keep a tension on the cables while allowing the cover or roof to move up and down. The means for keeping the cables under tension may be accomplished by various means as explained hereinafter.

Other objects, features and advantages ofthe invention will be apparent to those skilled in the art from the following detailed description taken in connection with the accompanying drawings in which:

Fig. 1 is a broken front view partly in vertical section of a storage apparatus for fluids constructed in accordance with and illustrating one form of the invention.

Fig. 2 is a broken front view of a storage apparatus similar to that shown in Fig. 1 showing a modified form of the cable tensioning on roof rotating means.

Fig. 3 is a view similar to that of Fig. 2 showing another form of the cable tensioni'ng or roof rotating means.

The present invention is illustrated in Fig. I of the drawings in connection With a relatively shallow oil storage tank of large diameter provided with a liquid sealed lift type roof o cover. A container of this type is adapted to hold a large volume of gas and vapors and may be connected with other tanks having fixed roofs to take care of their breathing requirements. The container as shown is also adapted to store liquid. The apparatus shown in Fig. 1 comprises acontainer'h'avw ing an upright cylindrical steel shell I'll attached to a bottom 12, the shell being provided with the usual top angle curb l4. A trough or launder [6 having an outer cylindrical wall l8 extends around the shell H3. The wall l8 has a top angle bracket 20, and is attached to an extension of the bottom plate I2 as shown. The launder [6' may be regarded as either inside or outside the container.

The shell 19 is preferably braced to prevent collapse by the weight of the launder liquid when the liquid level in the container is low or the container is empty. Suitable bracing is provided by "installing a sufflcient number of braces distributed around the inside of the shell l4, comprising a vertical rib or angle member 22, attached to the bottom l2, the shell re, and to the curb E4, and an angle brace 24 attached to the member 22 and to a foot-plate 26 fastened to the bottom plate l2.

The cover or roof for the container is of the lift type and comprises a cambered or cone-shaped plate 28 extending over the launder, and to which is attached in a fluid-tight manner a depending cylindrical sheet metal curtain wall or apron 30, which seals in the liquid in the launder iii. The cover is also preferably, but not necessarily, provided with a weather hood 32 which extends over the launder and may be bolted to the edge of the roof plate 28.

The lift is kept in its normal path of motion with respect to the shell ill or launder 56 by a stabilizing means which includes at least three flexible cables 34 distributed around the container, one end of each of which is anchored or pivoted to the upper part of the wall 36, and the other end of which is anchored or pivoted to a fixed point such as to Wall l8 somewhat below its top. Each cable 34 preferably includes a loop or eye at each end which is pivoted for movement over posts or stanchions 36 and 38 on the wall 36 and the wall I8, respectively, as shown. The respec tive ends of the cables are preferably located so that the fixed ends or stanchions 38 are at a somewhat lower level than the ends on stanchions 36 attached to the roof, even when the roof is in its lowest position, thus to always provide a downward strain on the roof a well as a rotational strain or tension. The cables 34 are of the same length and are mounted so that they are all taut; and at the same angle to the horizontal, which of course will be the case if all stanchions 36 are in the same relative positions on the roof, including their being the same distance from its center; and all stanchions 38 are in the same relative positions on a fixed part of the apparatus, including their being the same distance from the center of the tank or container. All stanchions of each set are preferably at the same level, although that is not essential. cables, however, must be at the same angle to the horizontal.

In Fig. 1 the means for maintaining a tension on the cables 34 comprises a series of upwardly curved tracks 46 mounted on the outside of the wall 36 and distributed therearound. Each track 40 may be welded to the wall 30 and be of flanged shape or of angle cross-section, as shown. The edge of the flange of each track rides on a flanged roller 42 mounted in a fixed position on the top of the wall It]. The roller extends toward the wall 36 and under the track. The mounting brackets include the angle sections 26. The tracks 46 are curved and set so that regardless of the position of the roof they engage therollers at all levels and keep the cables 34 taut. As the roof rises it is snubbed by the cables 34 and rotated to the right, pulling the tracks against the rollers 42. In the downward movement the roof rotates in the opposite direction with the tracks running down on the rollers and pulling the snubber cables taut so that the roof is kept in a level or normal position.

If one side of the roof should be loaded unequally as with snow or ice, and thereby be forced The.

down, the adjacent tracks will cause rotation of the roof against the action of the snubbers and the roof will be kept level. The cables and the tracks coact to stabilize the roof, and it will be apparent that the tracks need not be of the same number as the cables and that a track need not be placed in any particular position around the container with respect to a cable. One track may be sufficient in some cases, but two or more tracks are preferred. The track or tracks may be mounted on the tank or launder wall and the roller or rollers on the roof.

In the different figures of the drawings, the same reference characters are used to refer to the same or similar parts of the apparatus. The apparatus of Fig. 2 may comprise the same type of container as shown in Fig. 1, or may merely show or be a launder and roof section of a large oil storage tank, and the same is true for Fig. 3. On the other hand, the apparatus as shown in these views, as well as in Fig. 1, may not include a launder, since some other form of seal, such as fabric, may be used, or the lift may seal in the liquid in the container, as in a bell-type gas holder. If it is desired merely to store gases, a launder like the launder MS may be made in the earth, and the earth inside the launder gas-proofed and rounded to support the roof. In such a case the launder may be made of concrete.

The stabilizing apparatus of Figs. 2 and 3 are the same as that of Fig. 1 except that difierent means are used for maintaining a stress or tension on the cables 34 by applying a rotational stress on the roof. In Fig. 2 this stress is applied by a cable 44 and a weight 46 attached to one end thereof. One end of the cable 44 is provided with an eye which is mounted over a stanchion 48 on the outside of the wall 36. The cable is then passed over a sheave 50 on the rim of the wall I8, and down to support the weight 46. The stanchion 48 and the sheave 56 are preferably a considerable distance apart and it will not matter if the cable 44 engages or wraps around the wall 30. One or more cables 44 may be used on a roof, at least two being preferred, so that one can be mounted on the opposite side of the container from the other. The cable or cables 44 need not be mounted in any particular relation around the roof from the cable snubbers 34.

In Fig. 3 one or more weights 46 are used to effect the rotational tension on the roof and keep the cables 34 taut by passing a cable 52, one end of which is attached to the weight 46, over a sheave 54 attached to the rim of the Wall l8, and then attaching the other end of the cable to a roller carriage 56 which mounts a pair of flanged rollers 58. The flanged rollers 58 engage the opposite sides of a vertical track 60 which is welded or otherwise secured to the outside of the wall 30. The track 60 preferably has a T-cross-section with the stem of the T welded to the wall 30. The roller carriage 56 slides along the top of the wall is and the angle member 62 as the roof moves up and down, the weight 46 applying a constant tension on the cables 34 because the force is applied horizontally regardless of the position of the roof, as distinguished from the tension arrangement in Fig. 2. One or more of the tensioning units shOWn in Fig. 3 may be used on a roof and need not be positioned with respect to the snubber cables 34. In Figs. 2 and 3 the weights 46 apply a continuous tension on the cables 34 by the rotational force exerted on the roof.

In applying the snubbers to a tank construcsion member that serves, the purpose intended,

but it will be obvious to those skilled in the art that chains, flexible bands or rods or desirable combinations thereof that will provide the desired flexibility, will serve equally well.

In the event that the lift is high in, relation to I tank diameter, and a relatively long snubber is required, rollers may be provided on the, snubbers. where they contact or wrap around the tank or lift, to prevent excessive friction and wear. The term cable as used in the claims is intended to include any form of flexible "snubber having th characteristics essential to the restraining action required.

Usually, the most convenient points, of attachment for the lower or fixed ends of the snubbers will be on th wall of the tank, but the foundation or a post thereon which will provide a suitable xed point, will serve equally well when conditions are favorable for such construction.

Having described the invention in its preferred form. what is claimed as new is:

1. A mechanism for holding the vertically movable cover or" a stationary vertical cylindrical type fluid storage container to its normal path of motion with respect to the container as the volume of stored fluid changes, comprising a plurality of at least three spaced flexible cables of substantial and of equal length distributed around said cover, each cable having one end attached to the cover a substantial distance from its center and the other end attached to a fixed part of the container, each of said cables being attached to the cover and container in the same relative positions and all cables being mounted at the same angle with respect to a horizontal plane as determined in one direction around the cover, means separate from said cables for maintaining said cover under rotational tension with respect to said container and to thereby hold all of the flexible cables at the same angle with a horizontal plane as determined in one direction around the cover and to positively maintain said cables in a substantially taut condition, whereby said cover is caused to rotate with respect to said container when the cover moves up and down.

2. A mechanism as defined by claim 1 in which one end of each cable is attached to the periphery of the cover.

3. A mechanism as defined by claim 1 in which said cover is a liquid sealed bell and each cable has one end attach d on the outside of the bell, and in which each cabl Wraps partly around the bell as it moves down.

4. A mechanism for holding the vertically movable cover of a stationar vertical cylindrical type fluid storage container to its normal path of motion with respect to the container as the volume of stored fluid changes, comprising a plurality of at least three spaced flexible taut cables of substantial and equal length distributed around said cover, each cable having one end attached to the cover a substantial distance from its center and the other end attached to a fixed part of the container, each of said cables being attached to the cover and container in the same relative positions with one nd of each cable at a higher lev l than that of the other end, all ofsaid flexible cables being mounted at the same angle with; a horizontal plane as determined in one direction around the cover, and separate means for maintaining said cover under rotational. ten ionto maintain. said cables in a substantially taut condition, whereby said cover is caused to, rotate in, one direction with respect to said container when the cover moves up and to rotate; in the opposite direction when it moves dOWLL.

5. Amechanisrn. asdefined by claim 4 in which said; means omprises a plurality of similar track roller; units distributed around the container and cover and, operatively connected thereto, said units being constructed and arranged so as to cause said cover to take a rotational motion and thereby keep said cables substantially taut.

6. A mechanism, for holding a Vertically movable bellrtypc. lift :of. a, stationary vertical cylindrical type Iiuidstorago container to its normal path of motion with respect to the container as volume of stored fluid changes, comprising a plurality of at least three spaced flexible cables of; substantial and of equal length distributed around said lift, each cable having one end pivo nd to the: bait: as substantial distance from its center" the other end: pivoted to a fixed part of; the.- container structure; each of said cables being attached tn; the. lift and container in t e same relative positions; all, of said flexible cables b i g: mounted at the same angle with a. horizontal plane as determined in one direction around the lift, and a plurality of curved tracks distributed around and mounted on the side of said lift with ngaging rollers on said container, said tracks and rollers being arranged to maintain said cables in a substantially taut condition, whereby said lift is caused to rotate in one direction with respect to said container when the lift moves up, and to rotate in the opposite direction when it moves down.

7. A mechanism as defined by claim 6 in Which said container is provided with an annular launder for sealing liquid and in which said lift seals in the liquid in said launder.

8. An apparatus for holding fluids, comprising a vertical cylindrical type fluid storage container provided with a vertically movable cover having a normal path of motion with respect to the container as the volume of stored fluid changes, a plurality of at least three spaced flexible snubber cables of substantial and of equal length distributed around said cover, each cable having one end anchored to the cover a substantial distanc from its center and the other end anchored to a fixed part of the container at a level that is always lower than the anchoring points on the cover, said cables being attached to the cover and container in the same relative positions, all of said flexible cables being mounted at the same angle with a horizontal plane as determined in one direction around the cover, and a separate m ans associated with said cover for maintaining said cables in a substantially taut condition, whereby said cover is caused to rotate in one direction with respect to said container under the pull of said cables when the cover moves up, and to rotate in the opposite direction by the action of said means when th cover moves down.

9. An apparatus as defined by claim 8 in which said cover is a bell-type lift and said means comprises an upwardly curved track fixed to the side 7 of the lift and a roller mounted on the container engaging the under side of the track.

10. An apparatus for holding fluids, comprising a container including a Vertically movable belltype roof sealed with respect to the stationary part of the container, a plurality of at least three spaced flexible snubber cables of equal length distributed around the roof, each cable having one end anchored to the roof and the other end anchored to a fixed part of the apparatus, said cables being mounted in the same relative positions with respect to the roof, all of said flexible cables being mounted so that they assume the same angle with a horizontal plane as determined in one direction around the roof, and a separate means for applying a rotational tension on said cover to maintain said cables taut.

11. An apparatus as defined by claim 10 in which said roof seals in an annular launder.

12. An apparatus as defined by claim 10 in which said means comprises a track and roller unit mounted between the roof and container and in which said track curves upwardly at an angle in a direction generally opposite to that of the cables.

13. A mechanism for holding the movable cover of a stationary vertical cylindrical type fluid storage container to its normal path of motion with respect to the container as the volume of stored fluid changes, comprising a plurality of i at least three spaced flexible cables of substantial length distributed around said cover, each flexible cable having one end attached to the cover and the other end attached to a fixed part of the apparatus, all of said flexible cables being mounted at the same angle with a horizontal plane as determined in one direction around the cover and in the same relationship with respect to said cover, and means having no direct contact with the flexible cables for applying a torque to said cover to thereby positively maintain said cables in a taut condition whereby the said cover is caused to rotate with respect to said container when the cover moves up and down.

14. A mechanism as defined by claim 13 in which said means comprises a track and roller unit mounted between the roof and container and in which said track curves upwardly at an angle in a direction generally opposite to that of the cables.

15. A mechanism as defined by claim 13 in which said means comprises a cable mounted over a sheave on said container, one end of which is attached to the cover and the other end of which is attached to a weight arranged to apply a torque to said cover.

16. A mechanism as defined by claim 13 in which said means comprises a cable mounted over a sheave attached to said container, a weight mounted on one end of said cable, the other end of said cable being attached to a roller unit engaging a vertical track attached to the cover, said weight being arranged to apply a torque to said cover.

WILBUR G. LAIRD. 

